The 5 Foods With the Most Prebiotics to Support Gut Health

Prebiotics—a form of gut-friendly dietary fiber—have grown in popularity in recent years. Now, new preliminary research has pinpointed which five foods pack the most prebiotic content.

Dandelion greens, Jerusalem artichokes, garlic, leeks, and onions, are the most prebiotic-dense foods people can eat, according to a new study presented at NUTRITION 2023, the annual meeting of the American Society for Nutrition. The new research has not yet been peer-reviewed or published in a scientific journal.

Not only do prebiotics help support gut health, but prebiotic-rich foods also contain high amounts of fiber, an essential nutrient most Americans don’t get enough of.

“Eating prebiotic-dense foods has been indicated by previous research to benefit health,” study co-author Cassandra Boyd, a master’s student at San José State University, said in a news release. “Eating in a way to promote microbiome wellness while eating more fiber may be more attainable and accessible than you think.”

Here’s what to know about these prebiotic-rich foods, how prebiotics work to support gut and overall health, and how to easily add more prebiotics into your diet.

What Are Prebiotics?

Prebiotics and probiotics both benefit the body’s microbiome—the community of organisms that live inside all of us—but in different ways. While probiotics are living microorganisms, prebiotics are specialized plant fibers that can be thought of as fuel for the probiotics.

“[Prebiotics] can influence—in a beneficial way—the composition of one’s gut microbiota,” said Deborah Cohen, DCN, RDN, associate professor in the Department of Clinical and Preventive Nutrition Sciences at Rutgers University School of Health Professions.

Certain studies, for example, have linked higher prebiotic intake with better blood sugar management and absorption of essential minerals, and evidence of improved digestion and immune function.

However, more research is needed to fully understand how prebiotics can benefit the body.

“The exact health benefits and mechanisms of action of prebiotics are still the subject of ongoing research,” Scott Keatley, RD, co-owner of Keatley Medical Nutrition Therapy, told Health. “There is a need for more high-quality, human-based studies to better understand these topics.”

Common Foods Make It Easy to Consume More Prebiotics

For the new study, Boyd, along with her co-author John Gieng, PhD, assistant professor of nutritional sciences at San José State University, used previous findings to analyze the prebiotic content of 8,690 foods in the Food and Nutrient Database for Dietary Studies.

Of those foods, 37% contained prebiotics, with dandelion greens, Jerusalem artichokes, garlic, leeks, and onions containing the highest amounts (100–240 milligrams of prebiotics per gram of food).

Other foods found to have decent amounts of prebiotics were onion rings, creamed onions, cowpeas, asparagus, and Kellogg’s All-Bran cereal.

Onions were a surprising standout, according to the researchers. “Multiple forms of onions and related foods appear in a variety of dishes as both flavoring and main ingredients,” Boyd said in a statement to Health. “These foods are commonly consumed by Americans and thus would be a feasible target for people to increase their prebiotic consumption.”

Foods with fewer to no prebiotics included wheat-containing products, as well as dairy products, eggs, oils, and meats.

Adding More Prebiotic-Rich Foods to Your Diet

Though more research is needed on how prebiotics can benefit overall health, prebiotic-dense foods are still a good source of fiber, and thus, are an important part of a healthy, balanced diet.

Currently, only the International Scientific Association for Probiotics and Prebiotics has a daily recommended intake for prebiotics: 5 grams per day. According to Boyd, eating half a small onion—about 4 ounces—fulfills that recommendation.

The researchers behind this new study said they hope their findings will aid in future research about the benefits of prebiotics, and possibly even inform future dietary guidelines.

“Researchers could do more to understand the optimal amounts and types of prebiotics for different groups of people, such as those with certain health conditions, the elderly, and children,” Keatley said.

“There’s also a need for more studies on the interactions between prebiotics and other dietary components,” he added, “[as well as] the health benefits of different types of prebiotics, and the potential risks and benefits of prebiotic supplements.”

For now, experts recommend doing what you can to get more fiber in your diet.

“Try to get 25 to 35 grams of fiber per day in your diet—the average intake of Americans is around 15 grams,” Keatley said. “Slowly bring up your total and you may be amazed at how much better you feel, look, and your GI tract functions.”